ADVrider

Go Back   ADVrider > Bikes > Old's Cool > Airheads
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 03-15-2012, 12:35 PM   #1
rgears OP
Adventurer
 
Joined: May 2011
Location: New Bedford, Ma
Oddometer: 43
r90/6 pressure too high. Problem?

Hello again,
Well, I FINALLY figured out what was wrong with not having enough oil pressure, which ended up being a simple pinched pump cover O-ring, but at least I found several other things that would have eventually become an issue while I was in there. Problem now is I have too MUCH pressure. All kinds of back story here. I found a good thread elsewhere for the recomended rpm to psi numbers here.

I installed a pressure gauge and after start up, we're good at +100psi then quickly down to 75 range for warm up.
The problem is even after warm up, pressure isn't coming down below mid 60's, even at idle.
1100rpm 65(ish)psi idle
2200rpm 75psi
+3500rpm 80+psi

I'm not going to take it out much higher until I break in the engine and ALL the new parts.Yes, the pressure crushed the filter, but it has been in for a couple months throughout testing, so I wasn't too surprised.

I know this will cause damage, but I just have not heard of having too much pressure. What can cause this? I replaced both the timing valve and the ball-check valve in the filter canister and I know the forward main bearing has not spun. Part of the rebuild was a new pump (inner and outter rotor) and for break-in I'm running Castrol 20w-50.

Anyone have any ideas? Other than "damn..." Haha.
Thanks,
-Ryan
__________________
-Ryan
'76 R90/6
'70 CB450 -Almost cafe'd,
'82 CB750
'70 CL90 - Alive once more!
rgears is offline   Reply With Quote
Old 03-15-2012, 01:45 PM   #2
Max Headroom
lost in the '70s
 
Max Headroom's Avatar
 
Joined: Feb 2008
Location: New Zealand
Oddometer: 511
Those figures seem about normal to me.
__________________
'76 R90S silver smoke
'75 R90/6 hybrid

"Don't worry, it's not loaded."
last words of Chicago's Terry Kath before shooting himself in 1978
Max Headroom is offline   Reply With Quote
Old 03-15-2012, 01:46 PM   #3
H96669
A proud pragmatist.
 
H96669's Avatar
 
Joined: Nov 2009
Location: Hiding off Hwy 6, B.C.
Oddometer: 4,460
Idle speed is 6-800 on them.Yes it does make a difference, 17 years with an oil pressure gauge on the GS...I sure watched it a lot and did slightly twist the throttle a few times in traffic when hot to get a little extra lube moving.
__________________
Have tools, will travel!
H96669 is offline   Reply With Quote
Old 03-15-2012, 02:35 PM   #4
Biebs
BMW Airhead
 
Biebs's Avatar
 
Joined: Mar 2012
Location: Cave Creek AZ
Oddometer: 460
Yes those pressure seem normal for BMW. BMW runs high pressure on its cars as well as bikes.

To high of pressure may not let the oil have enough time to help remove the heat from the engine.


Why are you thinking this pressure is to high??

Again the pressured you listed seem correct.

Link to BMW Airhead oil lubication:

http://www.omnilex.com/public/bmw78/boxloob.pdf

Biebs screwed with this post 03-15-2012 at 02:42 PM
Biebs is offline   Reply With Quote
Old 03-15-2012, 02:39 PM   #5
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,632
If it's pressure that is caving in your filters that is too much. Make sure your oil pressure relief valve is not stuck.
supershaft is online now   Reply With Quote
Old 03-15-2012, 02:42 PM   #6
rgears OP
Adventurer
 
Joined: May 2011
Location: New Bedford, Ma
Oddometer: 43
Well, for one, after all the craziness I went through to get pressure again and damage from low pressure, I'm a bit paranoid. As for thinking the pressure is too high, having read other threads and write-ups about normal psi seemed like it should be lower, then again, all the write-ups I've read were not toward the /6's and prior, but either way the numbers just seemed on the high side of normal. However, I don't think any of them refered to a fresh rebuild.

So if those sound good, then I'll just move forward with engine break-in and actually get to enjoy riding again!

Thanks!
__________________
-Ryan
'76 R90/6
'70 CB450 -Almost cafe'd,
'82 CB750
'70 CL90 - Alive once more!
rgears is offline   Reply With Quote
Old 03-15-2012, 02:49 PM   #7
rgears OP
Adventurer
 
Joined: May 2011
Location: New Bedford, Ma
Oddometer: 43
Well, I think the filter caved because it had been the one I've been testing the engine with, so it just may not have been ready to take the suddenly high pressure once I got the pump sorted. I already installed a fresh one, so I'll check it after another ride tonight.
Just to make sure, I will check the timing valve to make sure it's not stuck. It's really only the idle pressure that has me concerned.
__________________
-Ryan
'76 R90/6
'70 CB450 -Almost cafe'd,
'82 CB750
'70 CL90 - Alive once more!
rgears is offline   Reply With Quote
Old 03-15-2012, 03:07 PM   #8
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,632
Cold oil can really jack up the pressure!
supershaft is online now   Reply With Quote
Old 03-15-2012, 05:37 PM   #9
Bigger Al
Still a stupid tire guy
 
Bigger Al's Avatar
 
Joined: Oct 2004
Location: Auburn, CA
Oddometer: 7,841
Are you using BMW filters? I've heard stories of aftermarket filters crushing.
__________________
"I'd rather wake up in the middle of nowhere than in any city on Earth."

Steve McQueen




Bigger Al is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 05:26 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014